OLED Pixel Electrode Segmentation for Dark Spot Detection
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Solution Overview
Problem
Organic light emitting display apparatuses face issues with dark spots due to foreign substances generated between the anode and cathode electrodes during the sputtering process, leading to inefficiencies in defect detection and repair.
Innovation Solution
A light emitting display apparatus with a repair structure that includes divided pixel electrodes connected through branch patterns with sensing nodes, allowing for automatic detection and compensation of resistance variations in subpixels, enhancing defect detection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foreign substances are generated between anode and cathode electrodes during sputtering process, then dark spots occur in the display, but defect detection reliability deteriorates
Solution Approach 1:
The pixel electrode is divided into multiple divided electrodes, and the connection electrode is divided into multiple division electrodes. This segmentation allows for individual detection of each subpixel region, enabling precise identification of dark spots caused by foreign substances without compromising overall display functionality.
Solution Approach 2:
A sensing node is introduced as an intermediary element between the divided electrodes and the detection system. This sensing node facilitates automatic detection of defects by measuring electrical characteristics, thereby improving defect detection reliability while maintaining display quality.
2Measurement precision
If divided pixel electrodes are used for defect detection, then detection precision improves, but device complexity increases
Solution Approach 1:
The divided electrodes and division electrodes serve multiple functions: they act as both display electrodes for image formation and as detection electrodes for defect identification. This multi-functionality reduces the need for separate detection structures, thereby limiting the increase in device complexity while maintaining high detection precision.
Solution Approach 2:
The electrode structure itself is utilized for detection purposes without requiring additional external detection components. The sensing nodes integrated into the electrode structure enable self-diagnosis of defects, simplifying the overall system architecture while achieving precise defect detection.
3Productivity
If automatic detection system is implemented, then productivity improves, but manufacturing precision requirements increase
Solution Approach 1:
The design accounts for variations in sensing node resistance by establishing detection thresholds that accommodate normal manufacturing tolerances. By adjusting detection parameters and using comparative measurement methods, the system maintains high productivity while being tolerant of reasonable variations in manufacturing precision.
Solution Approach 2:
The sensing nodes provide real-time feedback on electrode conditions, enabling automatic detection and classification of defects. This feedback mechanism allows the system to distinguish between normal manufacturing variations and actual defects, maintaining high production yield without requiring excessive manufacturing precision.
Data Source
AI summary
A light emitting display apparatus according to one or more embodiments of the present disclosure may include a light emitting element including a pixel electrode, an emission layer, and a common electrode, and a pixel circuit connected to the pixel electrode and configured to include at least one thin film transistor, the pixel electrode may include a first pixel divided electrode and a second pixel divided electrode spaced apart from each other, the first pixel divided electrode may be electrically connected to the pixel circuit through a first branch pattern having a first sensing node, and the second pixel divided electrode may be electrically connected to the pixel circuit through a second branch pattern having a second sensing node different from the first sensing node.